1. Field of the Invention
The present invention relates to a storage system and a power consumption reduction method for the storage system, and is suitable for use in a storage system using disks and a power consumption reduction method for the storage system.
2. Description of Related Art
In relation to the backup and archival of business data, a data de-duplication technique (hereinafter sometimes called “data de-duplication”) has been suggested, with which data will not be stored in disks redundantly to avoid unnecessary increase in the amount of data in disk arrays and improve the efficiency of the data capacity. With the data de-duplication technique, when the content of new data to be written in the disks, i.e., so-called write data, is identical to that of data already stored on the disks, the write data is not written to the disks. Judgment on whether the content of the write data is identical to that of the data already stored on the disks is usually conducted by a high-speed search using hashes (see, e.g., Patent Document 1).
A disk array is an apparatus having a number of disks. Operating these disks at the same time increases the power consumption in the entire disk array. To solve this problem, a technique for reducing power consumption by limiting the number of concurrently-active disks in the disk array so that the power consumption in the entire disk array can be reduced, thus producing a power-saving effect, has been suggested (see, e.g., Patent Document 2).
[Patent Document 1]U.S. Pat. No. 6,928,526[Patent Document 2]U.S. Pat. No. 5,423,046
With conventional storage systems using disks, no consideration has been given to the simultaneous performance of both the de-duplication of data in disks and power consumption control. Accordingly, even if disk arrays performing data de-duplication try to reduce power consumption by limiting the number of active disks, efficient disk operation control cannot be achieved because they have been designed with no consideration given to the disk access required in the de-duplication. Accordingly, unnecessary disks operate and an optimal power-saving effect cannot be produced.
This invention has been devised in light of the above points and aims to provide a storage system and a power consumption reduction method, capable of maximizing the data capacity efficiency and the power-saving effect when the data de-duplication and the disk operation control are performed simultaneously.